while it is positively related with the identified regulation. Conscientiousness is the tendency to show self-discipline, thoroughness and the need for achievement and its negative relationship with less self-determinated motivation and positive relationship with more self-determinated motivation to exercise may reflect the need for competence, such as suggest by Ingledew et al. (2004). Emotional stability (on the opposite end of Neuroticism) is negatively related with external and introjected regulation and could represent the tendency of the less self-regulated motivation exerciser to practice sport to avoid guilt or anxiety. Finally, Openness proved to be negatively related with external regulation and positively related with intrinsic motivation; this relationship is in accord with the results of previous studies (Ingledew et al., 2004) and could be explained by the need to satisfy the basic psychological need for autonomy.